Ethanol reforming for hydrogen production in a hybrid electric vehicle: process optimisation

This work is focused at optimizing an ethanol reforming process over a Ni/Cu catalyst to produce a hydrogen rich stream in order to feed a solid polymer fuel cell (SPFC). The effect of the reaction temperature, H2O/EtOH and O2/EtOH molar ratios of the feed to the reformer was studied under diluted conditions in order to maximize the hydrogen content and the CO2/COx molar ratio at the outlet of the ethanol reformer. Based on the experimental results, a detailed kinetic scheme of the ethanol reforming was discussed as a function of the temperature, special attention was paid to the role of oxygen in the reaction selectivity and coke formation. Moreover, the coke nature was evaluated by transmission electron microscopy (TEM) and TPO and TPH experiments. The tests carried out at on-board reformer conditions allowed a hydrogen rich mixture (33%) in the outlet reformer flow that can be even increased by water gas sift reactions downstream. The high hydrogen content of the flow to the fuel cell together with the stability of the Ni/Cu catalyst, fully demonstrated by long time runs, can be considered of high interest for SPFC applications.